Dropdown doesn't close on mousedown

[mgiuffrida]

The dropdown only closes when something else is "click"ded -- not when something else is "mousedown"deded.

Fiddle: https://jsfiddle.net/mgiuffrida/9cx5ezxo/

1. Click "Open" to open the dropdown.
2. Elsewhere on the same page, press down the mouse button.

Expected: Dropdown closes.
Actual: Dropdown stays open.

1. Drag the mouse to another position on the same page, and release the mouse button.

Expected: Dropdown closes.
Actual: Dropdown is still open.